Lessons Learned and Shared Plan for the worst. Hope for the best. Remember that hope is not a strategy.
Agnes
8 Lessons 1. Identify Susceptible Communities 2. Develop a Plan 3. Threat Recognition 4. Review Response Times 5. Training: Practice the Plan 6. Responding: Organization, Communication 7. Recovery 8. Debriefing and Revising the plan
Lesson 1 Identify Susceptible Communities
Identify Communities 2003 Flooding in New Alexandria; subject to tidal flooding June 2006, Huntington Flooding; subject to flooding from short intense storms and a combination of tide/rain
Identify Communities Susceptible to both tidal and riverine flooding Tidal flooding dominates e.g. Hurricane Isabel September 2003, 9.6 ft. tidal surge and 0.5 inches rain Noblis
Identify Communities Susceptible to both tidal and riverine flooding Riverine flooding dominates Lake located upstream e.g. Storm of June 2006, 4.0 ft. tide and 8.3 inches rain
Lesson 2 Develop a Plan
Basic Elements of a Plan
Basic Elements of a Plan Goals Prevent loss of life Minimize property damage Reduce disruptions to commerce human activities Meet regulatory requirements
Basic Elements of a plan Goals continued Reaching these goals requires: Threat identification Minimizing response times Goals achieved through Effective planning Effective communication Community involvement Education
Lesson 3 Threat Recognition Develop predictive tools
Prediction Tools Analysis Rainfall run-off hydrologic modeling SCS Tidal hydrology and review of historical tidal records HEC-RAS Hydraulic analysis and water surface profile determination
Prediction Tools Development continued Determine the topographic elevation at which the community starts to flood Use hydraulic simulations to determine WSEs with various tidal and discharge combinations Use hydraulic model to determine flood wave travel times and appropriate response times Develop mathematical tools that identify the combinations of tide and discharges that cause flooding above a targeted level Develop triggers (tides and rainfall) that cause flooding above the targeted level
Prediction Tools Flow Prediction Tool FENWICK SEC 1389 ROAD Actual Tide P Qgauge (USGS Cameron Run) Q barcroft Q 4 3 8210 Model Tidal Value Qgauge reg. for USGS Cameron Run Qhunt (Barcroft) Qhunt (based on USGS Cameron Run gauge) WSE 4 6899 0 8210 7.0 NOTES 1) Maximum Q=35,000; Maximum tide = 16' 2) P is rainfall in inches. For forecasting (prior to the event) use 24 hr storm duration. For monitoring during the event use12 hr duration.
Prediction Tools Maps
Rainfall/Tidal Flooding Chart
Lesson 4 Review Response Times
Prediction Tools Response Time Response Time -Two Critical Parts Hydrologic lead times: Time of concentration and hydrograph travel time (rainfall, antecedent moisture, basin characteristics) Agency response time: -emergency personnel and equipment placement -implement flood mitigation (i.e. sand bags) and evacuation - decision and communication time Effective lead time = Hydrologic lead time - Agency response
Lesson 5 Training: Practice the plan
Training The Flood Response Plan Safety How to get to the site What to expect in the field Where to park Where to stand Field instructions Unified command
Training How to get to the site
Lesson 6 Responding Organization and Communications
Information Flow During a Flooding Event
Organization Incident Command Stormwater Fire & Rescue Police
Response Report to the Doc Sign in and briefing Pick up Safety equipment GO bag Sign out Before heading out to the field
Flood Response DOC Staff Continuous Event Monitoring Purpose: to provide appropriate lead time for any action that may be required Monitor conditions and sensors every (5 to 15) minutes Record data Analyze data for trends Data used in deciding when to act and what to do
Response - Doc staff Flood Monitoring Daily forecasts NATIONAL WEATHER SERVICE: Regional forecast Private meteorological services (e.g.. Weather Bug Accuweather): More localized forecasts Track the event on radar prior to its arrival in our area Frequently monitor weather reports on local TV and radio
Electronic Monitoring Systems: Real time. CONTINUOUS EVENT MONITORING
Response Field Staff Appropriate response time is critical Response activities include: Moving vehicles/equipment from low areas Flood-fighting efforts sandbagging and pumping Road closures Evacuation Rescue
Lesson 7 Recovery
Recovery
Recovery
Lesson 8 Debriefing & Revising the plan
Debriefing
Revising the Plan Revise Prediction Tools Post analysis: review data and compare these with our predicted outcomes Use these data to refine models The Flood Response Plan is revised annually in the fall after the end of hurricane season
Discussion / Questions?
Contact Information Donald Demetrius, PhD, P.E. Stormwater Planning Division, Department of Public Works and Environmental Services 12000 Government Center Parkway Suite 449 Fairfax, VA 22035 703-324-5500 TTY 711 Camylyn Lewis, PE Office 561-372-2718 Cell: 703-627-6225
September 8, 2011 Tower 424 in Reston at Richmond Highway and Lorton Road
September 8, 2011 Tower 424 in Reston at Richmond Highway and Lorton Road
Thank You.